FOK,
Dumb question from an ancient...
During a typical departure, how long would you expect to be "stooging" around below FL100 at more than 250 kts? More than about a minute or two?
Unlike an arrival, where you might well be required to "hang around" below FL100 in a hold for far more than a few minutes.
My thought being, that there would be an order of magnitude difference between time 'at risk' (or distance covered 'at risk') between a departure and an arrival.
CJ